In an image forming apparatus, a wireless IC (Integrated Circuit) tag is installed on/in a toner cartridge, and a reader writer reads and write sorts of information from and to the wireless IC tag (See PATENT LITERATURE #1).
Meanwhile, when a communication error occurs between a reader and a wireless IC tag, another apparatus determines that the wireless IC tag is arranged at a null point of the reader, and changes a wireless transmission characteristic of the reader and thereby tries to avoid the null point (See PATENT LITERATURE #2).